A suspension processing device using an ultrasonic wave according to a conventional example has a function generator and the like, as an external circuit for drive control, in which an ultrasonic oscillator and a reflection plate are arranged as a pair through a flow channel unit in which suspension flows. The function generator is a waveform generator that generates a waveform signal for control to be applied to the ultrasonic oscillator. The suspension processing device applies the waveform signal to the ultrasonic oscillator such that a sound field is generated by the ultrasonic wave between the ultrasonic oscillator and the reflection plate, and captures fine particles, solids and the like inside the flow channel unit. Accordingly, the solids and the like are separated from the suspension.
Examples of the related art relating to the suspension processing described above include Japanese Patent No. 2723182 (Patent Document 1) and Japanese Patent Application Laid-Open Publication No. 2004-24959 (Patent Document 2).
Patent Document 1 describes a non-contact manipulation method of fine particles in suspension using an ultrasonic wave oscillated by a rectangular oscillator having a plurality of electrodes.
Patent Document 2 describes a technique of capturing a fine object at a node or an antinode of sound pressure in a standing wave sound field to be generated in a flow channel by installing an oscillator and a reflection plate in parallel in the flow channel, and causing an ultrasonic wave to be reflected by the reflection plate. As described in Patent Document 2, it is possible to concentrate and separate solids in a liquid by modulation of an input signal to the oscillator even with a combination of the single oscillator and the reflection plate.
Any one of the above-described examples of the related art describes a technique of capturing, conveying, concentrating, separating or filtering the fine particles, the solids, or the like in the suspension or a liquid medium in a non-contact manner using the ultrasonic wave to be generated by the ultrasonic oscillator.